1. Field of the Invention
The present invention relates to an intra-vascular device and method. More particularly, the present invention relates to a device for deployment of a stent for treatment of luminal, i.e., intra-vascular, diseases.
2. Description of Related Art
In stent deployment systems, a self-expanding stent was restrained within a sheath. After positioning of the stent at the desired location via fluoroscopic guidance, the physician retracted the sheath to deploy the stent, i.e., to expose the stent and allow it to self-expand. To completely deploy the stent, the physician had to retract the sheath over the entire length of the stent, which was relatively cumbersome and typically required the use of both hands of the physician in the case of long self-expanding stents.
To illustrate, FIG. 1 is a partially cutaway delivery system 100 for deploying a stent 102 in accordance with the prior art. Stent 102 is a radially self-expanding stent.
Delivery system 100 includes a pushrod 104 and a sheath 106, sometimes called a catheter sheath. Pushrod 104 includes a distal end 104D and a proximal end 104P. Stent 102 is placed over distal end 104D of pushrod 104 (while in other embodiments of the stent and pushrod, the stent could be located near the distal end of the pushrod which includes being over a portion of an end of the pushrod or being distal to a distal end of the pushrod). Distal end 104D further includes radiopaque markers that allow the location of distal end 104D and stent 102 to be precisely tracked. Proximal end 104P of pushrod 104 terminates within and is mounted to a handle 112 or extends through handle 112 and out a port 114 of handle 112.
Pushrod 104 is a hollow tube which acts as a guide wire lumen. A guide wire 116 can extend through pushrod 104 and distal end 104D. The guide wire 116 can further extend through handle 112 and out port 114.
Sheath 106 includes a distal end 106D and a proximal end 106P. Prior to deployment, stent 102 is radially compressed and restrained within distal end 106D of sheath 106. Proximal end 106P of sheath 106 extends into handle 112. Proximal end 106P of sheath 106 is coupled to an actuation button 118, sometimes called a thumb slider, of handle 112. Sheath 106 is a hollow tube which acts as a pushrod lumen. Pushrod 104 extends through sheath 106.
During use, stent 102 is placed over distal end 104D of pushrod 104 and is radially compressed and restrained within distal end 106D of sheath 106. Stent 102 is introduced intra-vascularly and guided to the treatment site, e.g., an aneurysm.
Once stent 102 is properly positioned, sheath 106 is retracted by retraction of actuation button 118 thus deploying stent 102. More particularly, stent 102 is self-expandable and as sheath 106 is retracted, stent 102 self-expands and is permanently deployed, e.g., anchored within a lumen of a patient. The guiding of a stent and deployment of a self-expanding stent are well known to those of skill in the art.
During deployment, sheath 106 must move the entire linear length X of stent 102 to completely uncover and thus deploy stent 102. Since actuation button 118 is connected to and moves sheath 106, actuation button 118 must also be moved the linear length X to retract sheath 106 over the entire linear length X of stent 102 as actuation button 118 and sheath 106 move in a strictly linear 1:1 motion.
In the case when stent 102 is a long self-expanding stent, length X is substantial, e.g., 200 mm or more. Accordingly, to accommodate the long travel of actuation button 118, handle 112 must also be very long and at least linear length X. However, long handles are cumbersome and difficult to manipulate.